Function fluid_synth_nwrite_float 

pub unsafe extern "C" fn fluid_synth_nwrite_float(
    synth: *mut fluid_synth_t,
    len: c_int,
    left: *mut *mut f32,
    right: *mut *mut f32,
    fx_left: *mut *mut f32,
    fx_right: *mut *mut f32,
) -> c_int